Airlines collect $21.46 billion in extra fees in 2010

Fees to check luggage, change reservations and upgrade to a seat with more legroom, among other charges, generated $21.46 billion for the world's 47 largest airlines last year, according to a new study.

The report by a Wisconsin airline consultant found that the revenue collected in 2010 from such ancillary fees represents a 775% increase in revenue compared with 2007, when 23 airlines reported collecting $2.45 billion.

The study by the consulting firm IdeaWorks shows that airlines have been enjoying strong growth in such revenue since the industry began adding extra fees in 2008 in response to the global economic recession.

The parent company that operates United and Continental airlines reported collecting $5 billion in ancillary fees from the soon-to-be merged carriers, the most of any airline company, according to the report.

Las Vegas-based Allegiant Travel Co. reported that ancillary revenue represents 29.2% of the airline's total revenue, the highest percentage of any airline, the report said.